Management and Outcomes of Acute Myocardial Infarction-Cardiogenic Shock in Uninsured Compared to Privately Insured Individuals

Abstract

Background:

There are limited data on uninsured patients presenting with acute myocardial infarction-cardiogenic shock (AMI-CS). This study sought to compare the management and outcomes of AMI-CS between uninsured and privately insured individuals.

Methods:

Using the National Inpatient Sample (2000–2016), a retrospective cohort of adult (≥18 years) uninsured admissions (primary payer - ‘self-pay’ or ‘no charge’) were compared to privately insured individuals. Inter-hospital transfers were excluded. Outcomes of interest included in-hospital mortality, temporal trends in admissions, use of cardiac procedures, do-not-resuscitate (DNR) status, palliative care referrals, and resource utilization.

Results:

Of 402,182 AMI-CS admissions, 21,966 (5.4%) and 93,814 (23.3%) were uninsured and privately insured. Compared to private insured individuals, uninsured admissions were younger, male, from a lower socio-economic status, had lower comorbidity, higher rates of acute organ failure, ST-segment elevation AMI-CS (77.3% vs. 76.4%), and concomitant cardiac arrest (33.8% vs. 31.9%) (all p<0.001). Compared to 2000, in 2016, there were more uninsured (adjusted odds ratio [aOR] 1.15 [95% confidence interval {CI} 1.13–1.17]; p<0.001) and less privately insured admissions (aOR 0.85 [95% CI 0.83–0.87]; p<0.001). Uninsured individuals received less frequent coronary angiography (79.5% vs. 81.0%), percutaneous coronary intervention (60.8% vs. 62.2%), mechanical circulatory support (54% vs. 55.5%), and had higher palliative care (3.8% vs. 3.2%) and DNR status use (4.4% vs. 3.2%) (all p<0.001). Uninsured admissions had higher in-hospital mortality (aOR 1.62 [95% CI 1.55–1.68; p<0.001) and resource utilization.

Conclusions:

Uninsured individuals have higher in-hospital mortality and lower use of guideline-directed therapies in AMI-CS compared to privately insured individuals.

INTRODUCTION

Insurance status has shown to be related to clinical outcomes in both the cardiac and non-cardiac literature.^{1, 2} As of 2017, the uninsured population in the United States is approximately 9%, compared to 67% of individuals who obtain private insurance.³ In patients with acute myocardial infarction (AMI), large retrospective studies have previously demonstrated the lack of health insurance and Medicaid status to be associated with worse mortality and higher readmission rates compared to patients with private insurance.^{2, 4, 5} Age impacts primary payer status, with a larger proportion of non-ST-segment AMI patients bearing Medicare insurance, whereas patients with ST-segment-elevation AMI have other forms of insurance.^{6, 7} Prior data from the AMI literature has noted insurance-specific differences between those with Medicare and Medicaid and other carriers. Specifically, Medicare patients are older, and have higher comorbidities, and therefore may receive less frequent guideline-directed therapies due to risk of complications.^{6, 7} In contrast, though Medicaid patients are younger, hospitals are reimbursed lesser for Medicaid patients, raising concerns that they might systematically receive less aggressive therapy.^{1, 2}

Cardiogenic shock (CS) constitutes the sickest spectrum of AMI, and continues to be associated with nearly 30–40% mortality and morbidity in the contemporary era.^8–18 Patients with AMI-CS frequently require intensive care unit hospitalizations, use of cardiac and non-cardiac procedures such as coronary angiography, percutaneous coronary intervention (PCI), temporary mechanical circulatory support (MCS), mechanical ventilation and hemodialysis.^8–18 As noted by our group previously, this high-acuity and resource heavy population have an average charge of $80,000–180,000.⁹ It conceivable that given the high costs associated with this disease process, that insurance status may play a role in the management and outcomes of these patients. There are limited data that suggests that clinical outcomes in AMI-CS populations will also vary based on insurance status.^{19, 20} However, these prior studies have largely focused on patients bearing certain types of insurance (Medicare, Medicaid, private, etc.) and therefore there is a paucity of contemporary data on uninsured patients. Typically, privately insured individuals receive the most aggressive care when presenting with an AMI, and therefore it is important to contrast the outcomes of uninsured group against this insurance group.^{1, 2, 6, 7}

Considering this background, using a nationally representative population, we sought to assess the management and outcomes of uninsured individuals compared to privately insured individuals presenting with AMI-CS. In addition, we evaluated the temporal trends in admissions, use of cardiac and non-cardiac procedures, and clinical outcomes of these populations.

MATERIAL AND METHODS

Study Population, Variables and Outcomes

The National (Nationwide) Inpatient Sample (NIS) is the largest all-payer database of hospital inpatient stays in the United States. NIS contains discharge data from a 20% stratified sample of community hospitals and is a part of the Healthcare Quality and Utilization Project (HCUP), sponsored by the Agency for Healthcare Research and Quality.²¹ Information regarding each discharge includes patient demographics, primary payer, hospital characteristics, principal diagnosis, up to 24 secondary diagnoses, and procedural diagnoses. The HCUP-NIS does not capture individual patients but captures all information for a given admission. Institutional Review Board approval was not sought due to the publicly available nature of this de-identified database. These data are available to other authors via the HCUP-NIS database with the Agency for Healthcare Research and Quality.²¹

Using the HCUP-NIS data from 2000–2016, a retrospective cohort study of adult admissions (≥18 years of age) with AMI in the primary diagnosis field (International Classification of Diseases 9.0 Clinical Modification [ICD-9CM] 410.x and ICD-10CM I21.x-22.x) and a secondary diagnosis of CS (ICD-9CM 785.51, ICD-10CM R57.0) were identified. The HCUP-NIS contains data on the expected primary payers as Medicare (includes fee-for-service and Medicare Advantage), Medicaid (includes fee-for-service and managed care), private insurance, self-pay, no charge, others, or missing. Consistent with prior literature, admissions in which the primary payer was designated as ‘self-pay’ or ‘no charge’ were considered uninsured and were compared to privately insured individuals.^{2, 4} Admissions with other primary payer categories, inter-hospital transfers and those without in-hospital mortality data were excluded. The Deyo’s modification of the Charlson Comorbidity Index was used to identify the burden of co-morbid diseases (Supplementary Table 1).²² Demographic characteristics, hospital characteristics, acute organ failure, mechanical circulatory support, cardiac procedures, and non-cardiac organ support use were identified for all admissions using previously used methodologies from our group.^23–39

The primary outcome was the in-hospital mortality in uninsured AMI-CS admissions compared to private insured individuals. Secondary outcomes included temporal trends in admissions, use of coronary angiography, PCI, MCS, use of do-not-resuscitate (DNR) status, palliative care referrals, hospitalization costs, length of hospital stay and discharge disposition in uninsured and privately insured individuals with AMI-CS. A sensitivity analysis was performed for the cohorts without DNR status, palliative care referral and those not discharged against medical advice.

Statistical Analysis

As recommended by HCUP-NIS, survey procedures using discharge weights provided with HCUP-NIS database were used to generate national estimates.^{40, 41} Using the trend weights provided by the HCUP-NIS, samples from 2000–2011 were re-weighted to adjust for the 2012 HCUP-NIS re-design.^{40, 41} Chi-square/one-way analysis of variance and t-tests were used to compare 2/≥2 categorical and continuous variables, respectively. Multivariable logistic regression was used to analyze trends over time (referent year 2000). All analyses were conducted accounting for survey nature (SURVEYMEANS, SURVEYLOGISTIC, and SURVEYFREQ), clustering of admissions within a hospital (HOSP_NIS), weighting (DISCWT), and stratification (NIS_STRATUM) of the NIS. The inherent restrictions of the HCUP-NIS database related to research design, data interpretation, and data analysis were reviewed and addressed.^{40, 41} Pertinent considerations include not assessing individual hospital-level volumes (due to changes to sampling design detailed above), treating each entry as an ‘admission’ as opposed to individual patients, restricting the study details to inpatient factors since the HCUP-NIS does not include outpatient data, and limiting administrative codes to those previously validated and used for similar studies. Univariable analysis for trends and outcomes was performed and was represented as odds ratio (OR) with 95% confidence interval (CI). Multivariable logistic regression analysis incorporating age, sex, race, socio-economic stratum, hospital characteristics, comorbidities, acute organ failure, AMI-type, cardiac procedures, non-cardiac procedures, DNR status and palliative care referral was performed for assessing temporal trends of in-hospital mortality. Multiple sub-group analyses stratifying by age (≤75 years vs. >75 years), sex (male/female), race (white/non-white), type of AMI-CS (STEMI-CS/NSTEMI-CS) and presence of cardiac arrest (yes/no) were performed to confirm the findings of the primary analysis. For the multivariable modeling, regression analysis with purposeful selection of statistically (liberal threshold of p<0.20 in univariate analysis) and clinically relevant variables was conducted. Two-tailed p<0.05 was considered statistically significant. All statistical analyses were performed using SPSS v25.0 (IBM Corp, Armonk NY).

RESULTS

In the period from January 1, 2000, to December 31, 2016, there were over 10 million AMI admissions, of which 402,182 constituted AMI-CS admissions without inter-hospital transfer. Primary payer status was not listed for 643 (0.2%) admissions. Medicare, Medicaid, and Others constituted 250,349 (62.1%), 26,321 (6.5%), and 9,732 (2.4%) respectively and were excluded. Uninsured and privately insured individuals constituted 21,966 (5.4%) and 93,814 (23.3%) admissions and were studied further. Compared to private insured individuals, uninsured individuals were younger, more often male, of non-white race, from a lower socio-economic status, had lower comorbidity and were more frequently admitted to rural hospitals (Table 1). Uninsured individuals had higher rates of acute organ failure, ST-segment elevation AMI-CS (77.3% vs. 76.4%), cardiac arrest (33.8% vs. 31.9%), invasive mechanical ventilation (45.4% vs. 40.6%), but lower use of pulmonary artery catheters and non-invasive ventilation compared to privately insured individuals (all p<0.001) (Table 1). During the 17-year study period, there was a steady increase in unadjusted and adjusted rates of uninsured AMI-CS admissions and a steady decrease in privately insured individuals (Figure 1A and 1B).

Table 1.

Characteristics of uninsured and private insured AMI-CS admissions

Characteristics		Uninsured (N=21,966)	Private Insured (N=93,814)	P
Age (years)		56.5±10.2	59.8±10.8	<0.001
Age >75 years		5.3%	9.6%	<0.001
Female sex		26.9	28.3	<0.001
Weekend admission		28.1	28.7	0.09
Race	White	52.9	63.3	<0.001
	Black	8.7	5.6
	Others a	38.4	31.1
Quartile of median household income for zip code	0–25 th	31.2	17.9	<0.001
	26 th -50 th	26.0	23.6
	51 st -75 th	24.7	27.3
	75 th -100 th	18.0	31.2
Charlson Comorbidity Index	0–3	61.0	51.2	<0.001
	4–6	34.2	40.6
	≥ 7	4.8	8.3
Hospital teaching status and location	Rural	6.0	5.1	<0.001
	Urban non-teaching	41.5	43.1
	Urban teaching	52.5	51.8
Hospital bed-size	Small	7.6	7.8	0.46
	Medium	23.9	24.1
	Large	68.6	68.2
Hospital region	Northeast	9.8	15.7	<0.001
	Midwest	17.6	23.8
	South	54.5	38.1
	West	18.2	22.4
AMI type	ST-segment elevation	77.3	76.4	0.004
	Non-ST-segment elevation	22.7	23.6
Acute organ failure	Respiratory	46.7	44.7	<0.001
	Renal	30.7	29.7	0.003
	Hepatic	11.1	9.2	<0.001
	Hematologic	10.4	11.1	0.002
	Neurologic	17.4	16.2	<0.001
Out of hospital cardiac arrest		33.8	31.9	<0.001
Pulmonary artery catheterization		5.9	7.6	<0.001
Invasive mechanical ventilation		45.4	40.6	<0.001
Non-invasive ventilation		2.3	2.6	0.004
Hemodialysis		2.4	2.6	0.08

Represented as percentage or mean ± standard deviation;

^aHispanic, Asian, Native American, Others

Abbreviations: AMI: acute myocardial infarction; CS: cardiogenic shock

Figure 1. Temporal trends of uninsured and privately insured AMI-CS admissions.

A: 17-year unadjusted trends in uninsured and privately insured AMI-CS admissions; all p<0.001 for trend over time; B: Adjusted multivariate logistic regression for temporal trends in uninsured and privately insured AMI-CS admissions (2000 as referent year); adjusted for age, sex, race, comorbidity, socio-economic stratum, hospital characteristics, and comorbidities; p<0.001 for trend over time.

Abbreviations: AMI: acute myocardial infarction; CS: cardiogenic shock

Coronary angiography, PCI, and MCS were used less frequently in uninsured individuals during the study period (Table 2). Temporal trend analyses showed an increase in utilization of coronary angiography and PCI during the 17-year period; however uninsured individuals consistently received these procedures less frequently (Figures 2A and 2B). There has been an overall decrease in total MCS use during the study period that is primarily due to a decrease in intra-aortic balloon pump utilization (Figures 2C and 2D). There has been a steady increase in percutaneous left ventricular assist device and extracorporeal membrane oxygenation use, with lower rates in the uninsured population (Table 2 and Figures 2E and 2F). The uninsured population had higher use of DNR status (4.4% vs. 3.2%) and higher rates of palliative care referral (3.8% vs. 3.2%) compared to privately insured individuals.

Table 2.

Clinical outcomes of uninsured and private insured AMI-CS admissions

Outcomes		Uninsured (N=21,966)	Private Insured (N=93,814)	P
Coronary angiography		79.5	81.0	<0.001
Percutaneous coronary intervention		60.8	62.2	<0.001
Mechanical circulatory support	Total	54.0	55.5	<0.001
	Intra-aortic balloon pump	51.7	53.1	<0.001
	Percutaneous LVAD	2.7	2.6	<0.001
	ECMO	0.7	1.0	<0.001
Do-not-resuscitate status		4.4	3.2	<0.001
Palliative care referral		3.8	3.2	<0.001
In-hospital mortality		34.7	25.8	<0.001
Length of stay (days)		8.9±10.7	9.3±9.9	<0.001
Hospitalization costs (x1000 US Dollars)		135±143	145±166	<0.001
Disposition	Home	68.3	55.9	<0.001
	Transfer	11.7	13.9
	Skilled nursing facility	7.1	15.8
	Home with home health care	11.1	14.2
	Against medical advice	1.7	0.3

Represented as percentage or mean ± standard deviation

Abbreviations: AMI: acute myocardial infarction; CS: cardiogenic shock; ECMO: extracorporeal membrane oxygenation; LVAD: left ventricular assist device; US: United States

Figure 2. Temporal trends in cardiac procedures in uninsured and privately insured AMI-CS admissions.

Seventeen-year trends of coronary angiography (A), PCI (B), total MCS (C), IABP (D), pLVAD* (E) and ECMO (F) in uninsured and privately insured AMI-CS admissions; all p<0.001 for trend

*The administrative codes for pLVAD were introduced in 2004, and therefore temporal trends are presented from 2005 onwards

Abbreviations: AMI: acute myocardial infarction; CS: cardiogenic shock; ECMO: extracorporeal membrane oxygenation; IABP: intra-aortic balloon pump; MCS: mechanical circulatory support; PCI: percutaneous coronary intervention; pLVAD: percutaneous left ventricular assist device

The all-cause in-hospital mortality in uninsured individuals was higher than that in privately insured individuals (34.7% vs. 25.8%; OR 1.53 [95% CI 1.48–1.58]; p<0.001). There was a consistent decrease in in-hospital mortality across both categories during this 17-year study period (Figure 3). In a multivariable logistic regression for in-hospital mortality, the uninsured AMI-CS admissions had higher mortality compared to privately insured individuals (OR 1.62 [95% CI 1.55–1.68; p<0.001) (Supplementary Table 2). The uninsured group had shorter hospital stay, lower hospitalization costs, fewer discharges to skilled nursing facilities and higher rates of discharges against medical advice (Table 2).

Figure 3. Temporal trends of in-hospital mortality in uninsured and privately insured AMI-CS admissions.

A: Unadjusted in-hospital mortality in uninsured and privately insured AMI-CS admissions; p<0.001 for trend over time; B: Adjusted multivariate logistic regression for temporal trends of in-hospital mortality in uninsured and privately insured AMI-CS admissions (2000 as referent year); adjusted for age, sex, race, comorbidity, socio-economic stratum, hospital characteristics, comorbidities, AMI type, acute organ failure, cardiac arrest, coronary angiography, percutaneous coronary intervention, mechanical circulatory support, invasive mechanical ventilation, acute hemodialysis; p<0.001 for trend over time.

Abbreviations: AMI: acute myocardial infarction; CS: cardiogenic shock

In pre-specified sub-groups stratified by age, sex, race, type of AMI-CS and presence of cardiac arrest, uninsured AMI-CS admissions consistently had higher in-hospital mortality than privately insured individuals (Figure 4). In a sensitivity analysis excluding those without DNR status, palliative care referral and not discharged against medical advice, the uninsured cohort continued to have higher in-hospital mortality (30.8% vs. 22.8%; unadjusted OR 1.51 [95% CI 1.46–1.56]; adjusted OR 1.60 [95% CI 1.55–1.65]; p<0.001).

Figure 4. Adjusted odds ratio for in-hospital mortality in uninsured AMI-CS admissions as compared to privately insured individuals.

Adjusted odds ratios*(with 95% confidence interval) for in-hospital mortality in uninsured AMI-CS admissions compared to privately insured individuals

*Adjusted for age, sex, race, comorbidity, socio-economic stratum, hospital characteristics, comorbidities, AMI type, acute organ failure, cardiac arrest, coronary angiography, percutaneous coronary intervention, mechanical circulatory support, invasive mechanical ventilation, acute hemodialysis

Abbreviations: AMI: acute myocardial infarction; CS: cardiogenic shock; IHM: in-hospital mortality NSTEMI: non-ST-segment elevation myocardial infarction; STEMI: ST-segment elevation myocardial infarction

DISCUSSION

In the largest study looking at the effects of being uninsured on the clinical management and outcomes of AMI-CS, we identify significant health care disparities. Slightly over 5% of all AMI-CS admissions during this 17-year study period were in individuals who were uninsured and were typically younger, male, of non-white race, and from a lower socio-economic status. Despite higher acuity, these individuals received less frequent coronary angiography, PCI, pulmonary artery catheterization, and MCS. The uninsured population had higher use of DNR status and palliative care referrals, shorter hospital stays and fewer discharges to skilled nursing facilities. Compared to privately insured individuals, uninsured AMI-CS admissions consistently had higher in-hospital mortality despite being younger and with fewer comorbidities.

The findings of this study appear to be consistent with the limited literature in the AMI-CS literature. In a 2019 study using the HCUP-National Readmissions Database (HCUP-NRD) data from 2010– 2014, Sud et al. demonstrated that in older ST-segment elevation AMI-CS (STEMI-CS) patients (≥60 years), Medicaid and private insurance patients had a similar incidence of 30-day unplanned readmissions compared to the Medicare populations.¹⁹ In 2018, Mahmoud et al studied AMI-CS population using the 2013–2014 HCUP-NRD database and demonstrated that there was a statistically significant lower 30-day readmission in private insurance patients compared to those with Medicaid and Medicare.⁵ This study does not comment on the uninsured population or further subdivide the self-pay population to provide comparative insights with the current study. A 2019 study by Ando et al in a population of STEMI-CS patients demonstrated safety net hospitals, which have a higher percentage of Medicaid and self-pay patients compared to non-safety net hospitals, were also associated higher mortality, lower rates of PCI, and higher median costs.²⁰ There was a decrease in the percentage of uninsured patients from 2014, likely due to the implementation of the Affordable Care Act, however further analyses of AMI-CS by insurance coverage, to look at the increase in Medicaid population is needed. Despite a consistent decrease in in-hospital mortality during this study period, the absolute unadjusted mortality for privately insured individuals in 2000 was lower than that achieved for uninsured individuals in 2016, suggestive of the persistent disparities in these two groups.

While there are limited data for the AMI-CS population, closer parallels can be drawn with insurance/income status with outcomes in the related cardiovascular disease literature. In a 2017 study by Pancholy et al, the authors use HCUP-NIS database spanning 2003–2014 to study the effect of insurance status on the adult STEMI population.⁴ In this study, the uninsured population was largely composed of individuals who had lower than the median income based on zip code. Uninsured patients were younger, male, with lower income and had similar lengths of stay and total charges, but slightly higher rates of CS, cardiac arrest, in-hospital mortality, and discharges against medical advice compared to patients with private insurance.⁴ Of note, this study included the five subcategories of insurance status, but did not directly compare uninsured with private insurance.⁴ Furthermore, the inclusion of Medicare and Medicaid populations might potentially cause an inclusion bias due to the different demographics of this population compared to uninsured and privately insured individuals.²

There are several potential explanations for the results seen in the current study. The uninsured population, though younger and with lower comorbidity, likely has significant contributors to in-hospital mortality such as higher rates of DNR status and palliative care referrals, higher rates of discharges against medical advice and differences in racial and geographic composition, all of which are known to influence clinical outcomes.³⁸ It is possible these may reflect behaviors and decisions in the hospital that may have resulted in increased mortality. It has been previously shown that black patients have poorer medical outcomes in AMI, due to a combination of comorbidities resulting in earlier presentation of disease, poorer health care access that may result in worse initial presentation of disease, and lower average socioeconomic status.⁴² Furthermore, though not measurable in this study, implicit bias based on socio-economic demographics may continue to impact the care for these minority populations. As noted in our baseline demographics, higher rates of uninsured populations were noted in southern United States. Prior studies have demonstrated patients from the South have higher rates of chronic cardiovascular risk factors and disease, including obesity, diabetes, and low physical activity.⁴³ This higher disease burden may contribute to the higher in-hospital mortality risk of the overall uninsured patients admitted for AMI-CS. Lastly, the lower cost and length of stay in the uninsured population may reflect the higher in-hospital mortality and faster discharges against medical advice or home. Therefore, insurance status appears to be closely related to social, economic, environmental, and racial factors and therefore, needs careful evaluation in future qualitative studies. Insurance status often serves as a surrogate for systematic socio-economic disparities, and therefore reflects the negatively reinforcing influences of age, race, sex, socio-economic status, and access to healthcare as demonstrated in literature.^{26, 38, 44–47} In addition to the above factors, provider perception of medical adherence may influence the final decision on whether PCI is offered to this population. Given the disastrous effects of stent thrombosis when dual antiplatelet therapy is not followed, providers may be apprehensive to offer PCI to a patient who may or may not be able to afford the needed medications.^48–50

There are several strengths to the current study. Currently, there are limited data on the outcomes of uninsured AMI-CS patients because most databases are skewed towards patients with public or private insurance through claims-based data collection.^{2, 51} As such, there are studies of AMI-CS in Medicare and Medicaid populations, but not in uninsured populations.^{5, 19, 20} The HCUP-NIS is unique in that it is insurance-agnostic unlike other large databases that are claims-based. Moreover, this study offers a direct comparison between uninsured patients with private insurance patients to minimize the effect of age disparity. This is particularly important since age is a strong risk factor for worse outcomes in AMI-CS.^{6, 9, 26, 44, 46, 47, 52, 53} By reducing such confounders, directly comparing populations, using a database without enriching specific populations, and collecting a large nationwide population data, this study describes the disparities associated with lack of insurance for these critically ill patients.

Limitations

This study has several limitations, some of which are inherent to the analysis of a large administrative database. The HCUP-NIS attempts to mitigate potential errors by using internal and external quality control measures. The lack of angiographic data, such PCI location, lesion classification, presence of multi-vessel disease, and revascularization failure, that may significantly influence outcomes, were not available in this database. There are limited data on patient and family specific limitations to therapeutic options which may influence the clinical outcomes in this population. The ‘self-pay’ category may either include extremes of socio-economic status, however this study is unable to distinguish between these groups due to the inherent limitations of this administrative database. The uninsured cohort left the hospital against medical advice more often (1.7% vs. 0.3%) and we are unable to comment on the outcomes of this population. Since this was an inpatient database only, we are unable to comment on the continued management of these patients in the outpatient setting. This study does not study post-hospital long-term complications after PCI and AMI-CS, which may result in additional health care utilization that might be challenging for the uninsured population. Despite these limitations, this study addresses a significant knowledge gap highlighting the clinical outcomes of uninsured patients at a national level that is unique to this database.

CONCLUSIONS

Lack of insurance is associated with less frequent use of guideline-directed cardiac procedures in AMI-CS. Furthermore, uninsured individuals had higher rates of DNR status use, palliative care referrals, less frequent discharges to skilled nursing facilities, and higher in-hospital mortality. Further quantitative and qualitative research is needed into the underpinnings of decision-making in this population to help address these persistent healthcare disparities in AMI-CS outcomes.

Supplementary Material

Supplemental Tables 1-2

Supplementary Table 1. Administrative codes used for identification of diagnoses and procedures

Supplementary Table 2. Predictors of mortality in AMI-CS

COMMENTARY.

What is new?

• There are limited data on the outcomes uninsured patients presenting with AMI-CS compared to those private insured

• Uninsured individuals received less frequent coronary angiography (79.5% vs. 81.0%), PCI (60.8% vs. 62.2%), and MCS (54% vs. 55.5%)

• Uninsured individuals had higher palliative care referral (3.8% vs. 3.2%), DNR status use (4.4% vs. 3.2%) (all p<0.001), and higher in-hospital mortality (34.7% vs. 25.8%; adjusted OR 1.62 [95% CI 1.55–1.68; p<0.001).

What are the clinical implications?

• Despite robust guidelines, uninsured individuals received less frequent guideline directed therapies and had worse in-hospital outcomes

• Insurance status may be a marker of worse socio-economic profile that may indicate systematic bias towards minorities and disadvantaged sections of the society

• Further research into health care inequalities in AMI-CS is warranted to improve clinical outcomes

ABBREVIATIONS

AMI

acute myocardial infarction

CI

confidence interval

CS

cardiogenic shock

DNR

do-not-resuscitate

HCUP

Healthcare Cost and Utilization Project

ICD-9CM

International Classification of Diseases-9 Clinical Modification

ICD-10CM

International Classification of Diseases-10 Clinical Modification

MCS

mechanical circulatory support

NIS

National/Nationwide Inpatient Sample

NRD

National Readmissions Database

OR

odds ratio

PCI

percutaneous coronary intervention

STEMI

ST-segment elevation myocardial infarction